Adenoviruses are preferred in many gene therapy applications as a vector to deliver the therapeutic gene. The cultivation and purification of adenoviruses containing therapeutic genes, such as tumor suppressor genes and other biological response modifiers, have become increasingly important for gene therapy and vaccine development. As studies of gene therapy progress to clinical trials, larger quantities of purified viral vectors are needed to deliver the therapeutic gene in treatment. The relatively large diameter (approximately 80 nm) and fragile structure of adenoviruses make their purification challenging using conventional methods, e.g., cesium chloride density centrifugation and gel filtration chromatography, which have scale limitations. Chromatographic protocols for purifying live adenoviruses are known, e.g., see U.S. Pat. No. 5,837,520, however, small amounts of contaminating proteins and incomplete virus particles, e.g., empty capsids, are found in virus preparations using these protocols. This is a significant problem since empty capsids and other protein contaminants can be immunogenic in vivo. Therefore, it would be advantageous to have an effective process that provides a sample of highly purified viable virus, while significantly reducing levels of incomplete virus particles. Improved virus purity without sacrifice to virus yield would be beneficial in large-scale adenovirus production.
Thus, there is a need in the art for improved purification methods for adenoviruses that can resolve live virus from incomplete viral particles and other contaminating proteins in the viral preparation. The present invention addresses this and other needs in the art.